Search Publications
Identification of AGN in the XMM-Newton X-ray survey of the SMC
Maitra, Chandreyee; Haberl, Frank; Cioni, Maria-Rosa L. +2 more
Context. Finding active galactic nuclei (AGN) behind the Magellanic Clouds (MCs) is difficult because of the high stellar density in these fields. Although the first AGN behind the Small Magellanic Cloud (SMC) were reported in the 1980s, it is only recently that the number of AGN known behind the SMC has increased by several orders of magnitude. <…
ISPY - NaCo Imaging Survey for Planets around Young stars. Discovery of an M dwarf in the gap between HD 193571 and its debris ring
Reffert, Sabine; Metchev, Stanimir; Rickman, Emily L. +19 more
Context. The interaction between low-mass companions and the debris discs they reside in is still not fully understood. A debris disc can evolve due to self-stirring, a process in which planetesimals can excite their neighbours to the point of destructive collisions. In addition, the presence of a companion could further stir the disc (companion-s…
CLIcK: a Continuum and Line fItting Kit for circumstellar disks
Pascucci, Ilaria; Henning, Thomas; Liu, Yao
Infrared spectroscopy with medium to high spectral resolution is essential to characterize the gas content of circumstellar disks. Unfortunately, conducting continuum and line radiative transfer of thermochemical disk models is too time-consuming to carry out large parameter studies. Simpler approaches using a slab model to fit continuum-subtracte…
Heavy metal enrichment in the intermediate He-sdOB pulsator Feige 46
Heber, U.; Latour, M.; Dorsch, M.
The intermediate He-enriched hot subdwarf star Feige 46 was recently reported as the second member of the V366 Aqr (or He-sdOBV) pulsating class. Feige 46 is very similar to the prototype of the class, LS IV - 14°116, not only in terms of pulsational properties, but also in terms of atmospheric parameters and kinematic properties. LS IV - 14°116 i…
Spectral observations of X Persei: Connection between Hα and X-ray emission
Zamanov, R.; Stoyanov, K. A.; Wolter, U. +2 more
We present spectroscopic observations of the Be/X-ray binary X Per obtained during the period 1999-2018. Using new and published data, we found that during "disc-rise" the expansion velocity of the circumstellar disc is 0.4-0.7 km s-1. Our results suggest that the disc radius in recent decades show evidence of resonant truncation of the…
Detection of spike-like structures near the front of type-II bursts
Hillaris, A.; Preka-Papadema, P.; Moussas, X. +6 more
Aims: We examine high time resolution dynamic spectra for fine structures in type II solar radio bursts
Methods: We used data obtained with the acousto-optic spectrograph receiver of the Artemis-JLS (ARTEMIS-IV) solar radio spectrograph in the 450-270 MHz range at 10 ms cadence and identified more than 600 short, narrowband features. The…
Interpretation through experimental simulations of phase functions revealed by Rosetta in 67P/Churyumov-Gerasimenko dust coma
Lasue, J.; Fulle, M.; Bertini, I. +3 more
Context. The dust-brightness phase curves that have been measured by the OSIRIS cameras on board the Rosetta spacecraft within the coma of comet 67P/Churyumov-Gerasimenko (67P) present a remarkable flattened u-shape.
Aims: Our goal is to compare these phase curves with those of tentatively analog dust samples to assess the key dust properties…
A VLBI study of the wind-wind collision region in the massive multiple HD 167971
Galván-Madrid, R.; Brandner, W.; Herrero-Illana, R. +7 more
Context. Colliding winds in massive binaries are able to accelerate particles up to relativistic speeds as the result of the interaction between the winds of the different stellar components. HD 167971 exhibits this phenomenon which makes it a strong radio source.
Aims: We aim at characterizing the morphology of the radio emission and its dep…
Chromospheric observations and magnetic configuration of a supergranular structure
Leenaarts, Jorrit; Robustini, Carolina; de la Cruz Rodríguez, Jaime +1 more
Context. Unipolar magnetic regions are often associated with supergranular cells. The chromosphere above these regions is regulated by the magnetic field, but the field structure is poorly known. In unipolar regions, the fibrillar arrangement does not always coincide with magnetic field lines, and polarimetric observations are needed to establish …
The discovery of a Li/Na-rich giant star in Omega Centauri: formed from the pure ejecta of super-AGB stars?
Salaris, M.; Bonifacio, P.; Monaco, L. +3 more
We report the discovery of two Li-rich giant stars (fainter than the red giant branch (RGB) bump) in the stellar system Omega Centauri using GIRAFFE-FLAMES spectra. These two stars have A(Li) = 1.65 and 2.40 dex and they belong to the main population of the system ([Fe/H] = -1.70 and -1.82, respectively). The most Li-rich of them (#25664) has [Na/…